Conventional wrenches generally can rotate a bolt or a nut only in one direction. Therefore, when using the wrenches, the users have to mount the nut or the head portion of the bolt by the box end of the wrench and rotate the wrench in one direction to tighten the nut or the bolt. When loosening the nut or the bolt, the users have to turn the wrench and re-mount the nut or the bolt and rotate the nut or the bolt in the opposite direction. Such actions take too much time and have a low efficiency. Although ratchet tools are allowed to be rotated without disengaging form the nut or the bolt, the ratchet tools involve too many parts and need a larger and thick head to receive the parts therein so that the ratchet tools are not suitable used in a narrow space.
The present invention relates to a wrench and comprises a handle having a ring-shaped head in which a toothed member is received. At least one protrusion extends radially inward from an inner periphery of the ring-shaped head so as to define at least one recess between two ends of the at least one protrusion. Two grooves are respectively defined in a top and a bottom of the at least one protrusion so as to receive two elastic members therein. A top cap and a lower cap are respectively mounted to the ring-shaped head, and the lower cap has at least one curved slot defined in a top surface thereof A toothed member is rotatably received in the ring-shaped head and located between the top cap and the lower cap. At least one pawl member is movably located in the at least one recess and engaged with the toothed member. The two elastic members bias a rear surface of the at least one pawl member in the at least one recess. A pin extends from a bottom of the at least one pawl member and is movably received in the at least one curved slot. The at least one curved slot is wider than a diameter of the pin of the at least one pawl member.
The object of the present invention is to provide a wrench which has a thin ring-shaped head and can be rotated in two opposite directions without removing the wrench from the object to be tightened or loosened.